With many types of machines, especially those used in and around the home, the relative ease with which they can be assembled and/or later partially disassembled for repair is generally not a compelling concern to either the manufacturer or the user. Particularly with mass-produced machines, assembly is repetitive by trained workers and the parts are easy to handle, either manually or by using appropriate equipment. Later repair may, if simple, be effected by the user or if more complicated, by a trained service person.
And the economic consequences of having such machine inoperative for a period of time are inconsequential or nil. Machines such as household appliances, wrist watches and the like are examples of such machines.
In sharp contrast, industrial machinery (for, e.g., manufacturing, construction, mining and the like) involving a substantial capital expenditure comes under much closer scrutiny when ease of assembly and later repair are being considered. In fact, assembly and repair (with attendant machine "downtime") can have a major economic impact on overall operating costs and are important factors in the buying decision. Buyers are more willing to pay a higher initial price for a machine which is easy to assemble and repair.
Some types of machinery are simply too large to make and ship as a single unit; they must be shipped in sections and pieces and assembled at the point of use. Machines known as draglines are but one example. It is apparent why ease of assembly becomes an important consideration. And if the machine is at a remote site and requires auxiliary equipment such as a crane or the like for assembly or to perform field repair, the costs associated with the machine escalate.
To cite but one example of a type of machine requiring field assembly, a known dragline has an upper machinery housing that is supported by and pivotably rotates on a ring-like structure. Rotation is by a drive arrangement having electric motors driving shafts, the pinion gears of which engage such structure.
When the dragline is assembled on site, components of the partially-disassembled drive arrangement are lowered onto and mounted to a machinery deck. A disadvantage of a known dragline is that the remaining components, e.g., the lower shaft bearing, bearing housing and pinion gear, must be separately installed from beneath the deck. Working space (between the deck and what is known as the "tub") is cramped and the components are very heavy and difficult to work with. And the time required to effect assembly or to perform later repair is, in view of the invention, unnecessarily extended.
Another disadvantage of the known drive arrangement is that the lower shaft bearing is retained in location on the shaft by the pinion and related hardware mounted at the shaft end. The pinion cannot be removed without also running the risk that the bearing might fall from the shaft.
Yet another disadvantage of the known arrangement is that if the bolts holding the bearing housing body become loosened or fall off, such body moves under force of gravity. The machine is very likely to be disabled thereby.
And the bearing housing is of the split type having two C-shaped halves. The halves of a split housing are easier to handle but more difficult to manufacture.
An improved drive arrangement overcoming some of the problems and shortcomings of the known drive arrangement would be an important advance in the art.